The purpose of the FIRST (Flexible Initial Retrovirus Suppressive Therapies) study is to determine whether it is better to start antiretroviral (AR) treatment with a protease inhibitor (PI) containing regimen, a nonnucleoside reverse transcriptase inhibitor (NNRTI) containing regimen, or a PI plus NNRTI containing regimen in PI- and NNRTI-naive, HIV-infected individuals. An important feature of this study is that the specific AR drugs used in each of the three regimen and those used after initial virologic failure are left to the discretion of each patient's clinician The study also includes two randomized substudies that will assign PI(s) and/or the NNRTI. This study will compare the impact of the three HAART strategies on long-term plasma HIV RNA levels and future AR treatment options over an anticipated study duration of 60 months. While the primary aim of this study is to rank order the effectiveness of the three HAART strategies, the planned secondary analyses will permit an improved understanding of reasons for differences in effectiveness.